Hello,
syzbot found the following crash on:
HEAD commit: f2b6e66e9885 Add linux-next specific files for 20180904
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=110d0dea400000
kernel config: https://syzkaller.appspot.com/x/.config?x=15ad48400e39c1b3
dashboard link: https://syzkaller.appspot.com/bug?extid=5f9fe77fc9b743772535
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
Unfortunately, I don't have any reproducer for this crash yet.
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+5f9fe77fc9b743772535@xxxxxxxxxxxxxxxxxxxxxxxxx
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113
IRQs not enabled as expected
fail_dump lib/fault-inject.c:51 [inline]
should_fail.cold.4+0xa/0x11 lib/fault-inject.c:149
WARNING: CPU: 1 PID: 10172 at kernel/softirq.c:169
__local_bh_enable_ip+0x1bb/0x230 kernel/softirq.c:169
Kernel panic - not syncing: panic_on_warn set ...
__should_failslab+0x124/0x180 mm/failslab.c:32
should_failslab+0x9/0x14 mm/slab_common.c:1557
slab_pre_alloc_hook mm/slab.h:423 [inline]
slab_alloc mm/slab.c:3378 [inline]
__do_kmalloc mm/slab.c:3716 [inline]
__kmalloc+0x63/0x720 mm/slab.c:3727
kmalloc include/linux/slab.h:518 [inline]
tty_buffer_alloc drivers/tty/tty_buffer.c:170 [inline]
__tty_buffer_request_room+0x2da/0x810 drivers/tty/tty_buffer.c:268
tty_insert_flip_string_fixed_flag+0x8d/0x1f0 drivers/tty/tty_buffer.c:313
tty_insert_flip_string include/linux/tty_flip.h:37 [inline]
pty_write+0x12c/0x1f0 drivers/tty/pty.c:121
tty_put_char+0x137/0x160 drivers/tty/tty_io.c:2865
__process_echoes+0x462/0x9b0 drivers/tty/n_tty.c:714
flush_echoes drivers/tty/n_tty.c:814 [inline]
__receive_buf drivers/tty/n_tty.c:1633 [inline]
n_tty_receive_buf_common+0x11d3/0x2c70 drivers/tty/n_tty.c:1727
n_tty_receive_buf+0x30/0x40 drivers/tty/n_tty.c:1756
tiocsti drivers/tty/tty_io.c:2171 [inline]
tty_ioctl+0x7e7/0x1870 drivers/tty/tty_io.c:2557
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:501 [inline]
do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685
ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702
__do_sys_ioctl fs/ioctl.c:709 [inline]
__se_sys_ioctl fs/ioctl.c:707 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457099
Code: fd b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff
ff 0f 83 cb b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f7cf6e7dc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f7cf6e7e6d4 RCX: 0000000000457099
RDX: 0000000020000040 RSI: 0000000000005412 RDI: 0000000000000004
RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000006
R13: 00000000004d0df8 R14: 00000000004c6736 R15: 0000000000000000
CPU: 1 PID: 10172 Comm: syz-executor7 Not tainted 4.19.0-rc2-next-20180904+
#55
======================================================
WARNING: possible circular locking dependency detected
4.19.0-rc2-next-20180904+ #55 Not tainted
------------------------------------------------------
syz-executor5/10168 is trying to acquire lock:
0000000024f4e687 (console_owner){-.-.}, at: log_next
kernel/printk/printk.c:498 [inline]
0000000024f4e687 (console_owner){-.-.}, at: console_unlock+0x7a7/0x10d0
kernel/printk/printk.c:2394
but task is already holding lock:
0000000010640b20 (&(&port->lock)->rlock){-.-.}, at: pty_write+0xf9/0x1f0
drivers/tty/pty.c:119
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&(&port->lock)->rlock){-.-.}:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x96/0xc0 kernel/locking/spinlock.c:152
tty_port_tty_get+0x20/0x80 drivers/tty/tty_port.c:288
tty_port_default_wakeup+0x15/0x40 drivers/tty/tty_port.c:47
tty_port_tty_wakeup+0x5d/0x70 drivers/tty/tty_port.c:390
uart_write_wakeup+0x44/0x60 drivers/tty/serial/serial_core.c:103
serial8250_tx_chars+0x4be/0xb60
drivers/tty/serial/8250/8250_port.c:1806
serial8250_handle_irq.part.23+0x1ee/0x280
drivers/tty/serial/8250/8250_port.c:1879
serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1865
[inline]
serial8250_default_handle_irq+0xc8/0x150
drivers/tty/serial/8250/8250_port.c:1895
serial8250_interrupt+0xfa/0x1d0
drivers/tty/serial/8250/8250_core.c:125
__handle_irq_event_percpu+0x1c8/0xa50 kernel/irq/handle.c:149
handle_irq_event_percpu+0xa0/0x1d0 kernel/irq/handle.c:189
handle_irq_event+0xa7/0x135 kernel/irq/handle.c:206
handle_edge_irq+0x20f/0x870 kernel/irq/chip.c:791
generic_handle_irq_desc include/linux/irqdesc.h:154 [inline]
handle_irq+0x18c/0x2e7 arch/x86/kernel/irq_64.c:78
do_IRQ+0x80/0x1a0 arch/x86/kernel/irq.c:246
ret_from_intr+0x0/0x1e
native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:57
arch_safe_halt arch/x86/include/asm/paravirt.h:94 [inline]
default_idle+0xc2/0x410 arch/x86/kernel/process.c:498
arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:489
default_idle_call+0x6d/0x90 kernel/sched/idle.c:93
cpuidle_idle_call kernel/sched/idle.c:153 [inline]
do_idle+0x3aa/0x580 kernel/sched/idle.c:262
cpu_startup_entry+0x10c/0x120 kernel/sched/idle.c:368
start_secondary+0x433/0x5d0 arch/x86/kernel/smpboot.c:271
secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:242
-> #1 (&port_lock_key){-.-.}:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x96/0xc0 kernel/locking/spinlock.c:152
serial8250_console_write+0x8e5/0xb20
drivers/tty/serial/8250/8250_port.c:3247
univ8250_console_write+0x5f/0x70
drivers/tty/serial/8250/8250_core.c:590
call_console_drivers kernel/printk/printk.c:1725 [inline]
console_unlock+0xace/0x10d0 kernel/printk/printk.c:2407
vprintk_emit+0x33a/0x910 kernel/printk/printk.c:1926
vprintk_default+0x28/0x30 kernel/printk/printk.c:1967
vprintk_func+0x7a/0x117 kernel/printk/printk_safe.c:398
printk+0xa7/0xcf kernel/printk/printk.c:2000
register_console+0x7e7/0xc00 kernel/printk/printk.c:2722
univ8250_console_init+0x3f/0x4b
drivers/tty/serial/8250/8250_core.c:685
console_init+0x5d4/0x891 kernel/printk/printk.c:2808
start_kernel+0x610/0x94e init/main.c:661
x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:452
x86_64_start_kernel+0x76/0x79 arch/x86/kernel/head64.c:433
secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:242
-> #0 (console_owner){-.-.}:
lock_acquire+0x1e4/0x4f0 kernel/locking/lockdep.c:3901
console_lock_spinning_enable kernel/printk/printk.c:1588 [inline]
console_unlock+0x814/0x10d0 kernel/printk/printk.c:2404
vprintk_emit+0x33a/0x910 kernel/printk/printk.c:1926
vprintk_default+0x28/0x30 kernel/printk/printk.c:1967
vprintk_func+0x7a/0x117 kernel/printk/printk_safe.c:398
printk+0xa7/0xcf kernel/printk/printk.c:2000
fail_dump lib/fault-inject.c:44 [inline]
should_fail+0xb04/0xd86 lib/fault-inject.c:149
__should_failslab+0x124/0x180 mm/failslab.c:32
should_failslab+0x9/0x14 mm/slab_common.c:1557
slab_pre_alloc_hook mm/slab.h:423 [inline]
slab_alloc mm/slab.c:3378 [inline]
__do_kmalloc mm/slab.c:3716 [inline]
__kmalloc+0x63/0x720 mm/slab.c:3727
kmalloc include/linux/slab.h:518 [inline]
tty_buffer_alloc drivers/tty/tty_buffer.c:170 [inline]
__tty_buffer_request_room+0x2da/0x810 drivers/tty/tty_buffer.c:268
tty_insert_flip_string_fixed_flag+0x8d/0x1f0
drivers/tty/tty_buffer.c:313
tty_insert_flip_string include/linux/tty_flip.h:37 [inline]
pty_write+0x12c/0x1f0 drivers/tty/pty.c:121
tty_put_char+0x137/0x160 drivers/tty/tty_io.c:2865
__process_echoes+0x462/0x9b0 drivers/tty/n_tty.c:714
flush_echoes drivers/tty/n_tty.c:814 [inline]
__receive_buf drivers/tty/n_tty.c:1633 [inline]
n_tty_receive_buf_common+0x11d3/0x2c70 drivers/tty/n_tty.c:1727
n_tty_receive_buf+0x30/0x40 drivers/tty/n_tty.c:1756
tiocsti drivers/tty/tty_io.c:2171 [inline]
tty_ioctl+0x7e7/0x1870 drivers/tty/tty_io.c:2557
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:501 [inline]
do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685
ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702
__do_sys_ioctl fs/ioctl.c:709 [inline]
__se_sys_ioctl fs/ioctl.c:707 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
other info that might help us debug this:
Chain exists of:
console_owner --> &port_lock_key --> &(&port->lock)->rlock
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&(&port->lock)->rlock);
lock(&port_lock_key);
lock(&(&port->lock)->rlock);
lock(console_owner);
*** DEADLOCK ***
5 locks held by syz-executor5/10168:
#0: 000000000d2dc9cb (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353
#1: 000000009f357d4f (&o_tty->termios_rwsem/1){++++}, at:
n_tty_receive_buf_common+0xeb/0x2c70 drivers/tty/n_tty.c:1690
#2: 0000000005bec1a7 (&ldata->output_lock){+.+.}, at: flush_echoes
drivers/tty/n_tty.c:812 [inline]
#2: 0000000005bec1a7 (&ldata->output_lock){+.+.}, at: __receive_buf
drivers/tty/n_tty.c:1633 [inline]
#2: 0000000005bec1a7 (&ldata->output_lock){+.+.}, at:
n_tty_receive_buf_common+0x119b/0x2c70 drivers/tty/n_tty.c:1727
#3: 0000000010640b20 (&(&port->lock)->rlock){-.-.}, at:
pty_write+0xf9/0x1f0 drivers/tty/pty.c:119
#4: 0000000073842333 (console_lock){+.+.}, at: console_trylock_spinning
kernel/printk/printk.c:1650 [inline]
#4: 0000000073842333 (console_lock){+.+.}, at: vprintk_emit+0x31f/0x910
kernel/printk/printk.c:1925
stack backtrace:
CPU: 0 PID: 10168 Comm: syz-executor5 Not tainted 4.19.0-rc2-next-20180904+
#55
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113
print_circular_bug.isra.34.cold.55+0x1bd/0x27d
kernel/locking/lockdep.c:1222
check_prev_add kernel/locking/lockdep.c:1862 [inline]
check_prevs_add kernel/locking/lockdep.c:1975 [inline]
validate_chain kernel/locking/lockdep.c:2416 [inline]
__lock_acquire+0x3449/0x5020 kernel/locking/lockdep.c:3412
lock_acquire+0x1e4/0x4f0 kernel/locking/lockdep.c:3901
console_lock_spinning_enable kernel/printk/printk.c:1588 [inline]
console_unlock+0x814/0x10d0 kernel/printk/printk.c:2404
vprintk_emit+0x33a/0x910 kernel/printk/printk.c:1926
vprintk_default+0x28/0x30 kernel/printk/printk.c:1967
vprintk_func+0x7a/0x117 kernel/printk/printk_safe.c:398
printk+0xa7/0xcf kernel/printk/printk.c:2000
fail_dump lib/fault-inject.c:44 [inline]
should_fail+0xb04/0xd86 lib/fault-inject.c:149
__should_failslab+0x124/0x180 mm/failslab.c:32
should_failslab+0x9/0x14 mm/slab_common.c:1557
slab_pre_alloc_hook mm/slab.h:423 [inline]
slab_alloc mm/slab.c:3378 [inline]
__do_kmalloc mm/slab.c:3716 [inline]
__kmalloc+0x63/0x720 mm/slab.c:3727
kmalloc include/linux/slab.h:518 [inline]
tty_buffer_alloc drivers/tty/tty_buffer.c:170 [inline]
__tty_buffer_request_room+0x2da/0x810 drivers/tty/tty_buffer.c:268
tty_insert_flip_string_fixed_flag+0x8d/0x1f0 drivers/tty/tty_buffer.c:313
tty_insert_flip_string include/linux/tty_flip.h:37 [inline]
pty_write+0x12c/0x1f0 drivers/tty/pty.c:121
tty_put_char+0x137/0x160 drivers/tty/tty_io.c:2865
__process_echoes+0x462/0x9b0 drivers/tty/n_tty.c:714
flush_echoes drivers/tty/n_tty.c:814 [inline]
__receive_buf drivers/tty/n_tty.c:1633 [inline]
n_tty_receive_buf_common+0x11d3/0x2c70 drivers/tty/n_tty.c:1727
n_tty_receive_buf+0x30/0x40 drivers/tty/n_tty.c:1756
tiocsti drivers/tty/tty_io.c:2171 [inline]
tty_ioctl+0x7e7/0x1870 drivers/tty/tty_io.c:2557
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:501 [inline]
do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685
ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702
__do_sys_ioctl fs/ioctl.c:709 [inline]
__se_sys_ioctl fs/ioctl.c:707 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457099
Code: fd b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 f
Lost 7 message(s)!
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113
panic+0x238/0x4e7 kernel/panic.c:184
__warn.cold.8+0x163/0x1ba kernel/panic.c:536
report_bug+0x252/0x2d0 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:178 [inline]
do_error_trap+0x1fc/0x4d0 arch/x86/kernel/traps.c:296
do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:316
invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:996
RIP: 0010:__local_bh_enable_ip+0x1bb/0x230 kernel/softirq.c:169
Code: 44 00 00 5b 41 5c 41 5d 5d c3 80 3d b6 e2 61 07 00 0f 85 3c ff ff ff
48 c7 c7 40 f4 28 87 c6 05 a2 e2 61 07 01 e8 a5 26 fe ff <0f> 0b e9 22 ff
ff ff 4c 89 e7 e8 d6 56 16 00 e9 68 ff ff ff 0f 0b
RSP: 0018:ffff880189fa5cb8 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 0000000000000201 RCX: ffffc9000288c000
RDX: 0000000000040000 RSI: ffffffff8163ba91 RDI: ffff880189fa59a8
RBP: ffff880189fa5cd0 R08: ffff880188bd2140 R09: fffffbfff1031404
R10: fffffbfff1031404 R11: ffffffff8818a023 R12: ffffffff8608e7f4
R13: ffff880188bd2140 R14: ffffc90011f27060 R15: dffffc0000000000
__raw_read_unlock_bh include/linux/rwlock_api_smp.h:251 [inline]
_raw_read_unlock_bh+0x30/0x40 kernel/locking/spinlock.c:272
ebt_do_table+0x1c14/0x2170 net/bridge/netfilter/ebtables.c:307
ebt_nat_in+0x65/0x80 net/bridge/netfilter/ebtable_nat.c:64
ebt_nat_out+0x25/0x30 net/bridge/netfilter/ebtable_nat.c:64
nf_hook_entry_hookfn include/linux/netfilter.h:119 [inline]
nf_hook_slow+0xc2/0x1c0 net/netfilter/core.c:511
nf_hook include/linux/netfilter.h:242 [inline]
NF_HOOK include/linux/netfilter.h:285 [inline]
__br_forward+0x534/0xdc0 net/bridge/br_forward.c:113
br_flood+0x85b/0x990 net/bridge/br_forward.c:240
br_dev_xmit+0x111b/0x1810 net/bridge/br_device.c:103
? 0xffffffff81000000
__netdev_start_xmit include/linux/netdevice.h:4313 [inline]
netdev_start_xmit include/linux/netdevice.h:4322 [inline]
xmit_one net/core/dev.c:3216 [inline]
dev_hard_start_xmit+0x272/0xc10 net/core/dev.c:3232
__dev_queue_xmit+0x2ab2/0x3870 net/core/dev.c:3802
dev_queue_xmit+0x17/0x20 net/core/dev.c:3835
neigh_hh_output include/net/neighbour.h:473 [inline]
neigh_output include/net/neighbour.h:481 [inline]
ip_finish_output2+0x1063/0x1860 net/ipv4/ip_output.c:229
ip_do_fragment+0x21a2/0x2ae0 net/ipv4/ip_output.c:678
ip_fragment.constprop.49+0x179/0x240 net/ipv4/ip_output.c:549
ip_finish_output+0x6e4/0xfa0 net/ipv4/ip_output.c:315
NF_HOOK_COND include/linux/netfilter.h:276 [inline]
ip_output+0x223/0x880 net/ipv4/ip_output.c:405
dst_output include/net/dst.h:444 [inline]
ip_local_out+0xc5/0x1b0 net/ipv4/ip_output.c:124
ip_send_skb+0x40/0xe0 net/ipv4/ip_output.c:1441
udp_send_skb.isra.41+0x6b7/0x11d0 net/ipv4/udp.c:829
udp_push_pending_frames+0x5c/0xf0 net/ipv4/udp.c:857
udp_sendmsg+0x178a/0x38e0 net/ipv4/udp.c:1148
udpv6_sendmsg+0x296a/0x36b0 net/ipv6/udp.c:1201
inet_sendmsg+0x1a1/0x690 net/ipv4/af_inet.c:798
sock_sendmsg_nosec net/socket.c:622 [inline]
sock_sendmsg+0xd5/0x120 net/socket.c:632
__sys_sendto+0x3d7/0x670 net/socket.c:1787
__do_sys_sendto net/socket.c:1799 [inline]
__se_sys_sendto net/socket.c:1795 [inline]
__x64_sys_sendto+0xe1/0x1a0 net/socket.c:1795
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457099
Code: fd b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff
ff 0f 83 cb b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f0550d94c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f0550d956d4 RCX: 0000000000457099
RDX: 0000000000000000 RSI: 0000000020000300 RDI: 0000000000000004
RBP: 00000000009300a0 R08: 00000000200002c0 R09: 000000000000001c
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004d4cc8 R14: 00000000004c91af R15: 0000000000000000
Dumping ftrace buffer:
(ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..
---
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